In hierarchical routing, the nodes of a communication network are grouped (e.g., classified) into different clusters. The clusters at a particular level of the routing hierarchy can be grouped into higher-level clusters, and this process can iterate recursively. At the highest level of the routing hierarchy, there is a single top-level cluster representing the entire network. Typically, each cluster is represented by a single logical node at the next higher level of the routing hierarchy. The ability to use a single logical node to represent a cluster of connected nodes limits the number of topological elements generating updates on their states, which can significantly improve network scalability. To simplify routing across the clusters, each cluster advertises only a summary, or an aggregated view, of its internal structure to other nodes (which may be single nodes or other clusters) outside the cluster.